Conventional electronic device manufacturing systems may include multiple process chambers and load lock chambers. Each of the chambers and load lock chambers are aligned within one plane. Such chambers may be included in cluster tools where a plurality of process chambers may be disbursed about a transfer chamber, for example. These systems and tools may employ transfer robots that may be housed within the transfer chamber to transport substrates between the various process chambers and load lock chambers. For example, the transfer robot may transport a substrate from process chamber to process chamber, from load lock chamber to process chamber, and/or from process chamber to load lock chamber within a tool. Efficient and precise transport of substrates between the various system chambers may improve system throughput, thereby lowering overall operating costs. Furthermore, reduced system size is sought after because distances that the substrates may need to move are reduced. However, if additional process steps are to be added, such additional processing may be accomplished by adding additional process chambers, sometimes as a retrofit. One known way to add on process chambers is to add an additional transfer chamber and transfer robot by using a pass-through chamber. However, the addition of an extra conventional transfer chamber may require additional floor space that may not be readily available.
Accordingly, improved systems, apparatus, and methods for efficient and precise movement of substrates and which allow the addition of more process chambers are desired.